When to plant watermelons in Oklahoma City: 15 April – 1 August

In Oklahoma City, watermelon: sow for seedlings from 25 February to 4 July; plant into a greenhouse from 25 March to 1 August; plant out into open ground from 15 April to 1 August. For plants and seeds, the places nearby include Smith Farm and Garden (garden centre, 6 km); addresses and opening hours are below.

Watermelon in Oklahoma City: soil, season and weather

In Oklahoma City the soil, not frost, sets the date: the last frost is over around 14 March, but the top 7 cm of soil reaches 18 °C — the minimum on the watermelon card — only around 15 April, 32 days later.

Last spring frost	14 March
Top 7 cm of soil at 18 °C	15 April, 32 days after the last frost
Into an unheated greenhouse	25 March – 1 August; March outside: 7.2 °C at night, 19.2 °C by day; card 18–35 °C
First autumn frost	10 November, 209 days after the start
Days in the bed to the first harvest (card)	59
First harvest, if planted in this window	13 June – 29 September
Days left for picking	150
Daylight	12:02 on 18 March, 13:04 on 15 April
Watering outdoors when fruiting (card)	every 5 days; the driest month, November, has 5 rainy days

The same dates in Oklahoma City hold for Cucumber, Bell Pepper, Eggplant, Zucchini and Pumpkin.

Watermelon in Oklahoma City: care after planting

Planted on 15 April: in the first weeks water every 5 days.

Feeding, by the card’s schedule from that day:

15 April — feed: balanced (NPK)

Pests and diseases of watermelon to watch for:

Dates count from the first planting day of the window above; a later planting moves them by as many days.

Weather in Oklahoma City during the watermelon season

No month of the season averages above the watermelon card's 18–35 °C by day; the warmest, July, averages 34.2 °C. Months that stay below 18 °C even by day on average: November (16.8 °C). Nights average below 18 °C in April, May and October, November (6.7–16.2 °C).

Month	Day, °C	Night, °C	Rain, mm	Rainy days	Daylight on the 15th
April	22.6	10.7	123	10	13:04
May	26.6	16.2	119	12	14:01
June	31.7	21.4	93	9	14:32
July	34.2	23.8	68	9	14:20
August	33.4	23.2	70	8	13:31
September	30.1	19.8	87	7	12:26
October	23.9	13.2	85	7	11:20
November	16.8	6.7	50	5	10:19

ERA5 2016–2025, Open-Meteo

Watermelon in nearby cities

Around Oklahoma City, Fort Worth is 24 days earlier and Wichita 17 days later.

City	Distance	Date	Difference
Lawton	126 km	4 April – 2 August	11 days earlier
Tulsa	157 km	29 April – 8 August	14 days later
Wichita	247 km	2 May – 21 July	17 days later
Fort Smith	285 km	1 May – 9 August	16 days later
Fort Worth	305 km	22 March – 21 August	24 days earlier
Dallas	306 km	27 March – 26 August	19 days earlier

Where to buy watermelon plants and seeds near Oklahoma City

Buy plants ready to set out from 15 April to 1 August (from 25 March to 1 August for an unheated greenhouse); seed for raising your own is sown from 25 February to 4 July. Within 15 km of Oklahoma City OpenStreetMap lists 3 garden centres, 2 farm-supply shops and 4 markets (collected 20 October 2026).

Facebook Marketplace Exchange Location — market
North May Avenue 3128, 73112 Oklahoma City · 5 km
Walmart Garden Center — garden centre
7 km
Bi-Rite Market — market
3 km
Smith Farm and Garden — garden centre
3733 NW 10th Street, 73107 Oklahoma City · Mon–Fri 08:30–17:30; Sat 09:00–13:00; Sun, public holidays closed · 6 km · smithfarmandgarden.com

Each window starts on the Greenly calendar date and ends on the last day that still leaves the crop’s days to harvest (from its card) before the average first autumn frost, plus six weeks of picking for crops harvested over weeks (tomatoes, peppers, aubergines, cucumbers, courgettes, pumpkins, watermelons, beans) — our rule; earlier in the window is safer.

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